It is well known that plastic compositions may be molded and cast by certain well known techniques in which the end product can be either soft or spongy, flexible or possessing certain degrees of rigidity in order to meet the necessary objectives in the use of such material.
In the art of shoe making, it has been known to make insoles for footwear by building up a composite made up of a number of different plies. Heretofore insoles have been made by layering a ply of board or composition material, a ply of fairly firm but flexible cushioning material, and a ply of leather or plastic material to impart a final surface appearance of a desired characteristic. In making up an insole from a multi-ply composition, it has been the practice to die cut each one of the plies separately, relate them in a stacked position with the use of a suitable adhesive, and to last the leather or plastic ply to the cushion and the board plies so that the leather or plastic ply encases the other plies in the final construction of the insole.
Such prior techniques are expensive because it requires many separate operations and a great deal of manual labor in die cutting the separate plies, assembling the plies in proper order, and performing the necessary lasting operation to produce the final insole.